The invention relates to a waste compactor, of simplified construction and of small dimensions, which is particularly suitable for positioning under or near the counter of a bar, cafeteria or other small restaurant business, for the purpose of compacting empty plastic bottles, glasses, cups and other small items of used tableware made from plastic material and/or paper, and/or other small solid wastes possibly including liquid residues, with the aim of substantially limiting the volume occupied by these wastes and thus facilitating their disposal by the producers of these wastes and by the parties responsible for collecting them and transporting them to the final recycling and/or disposal centres. The compactor according to the invention is also capable of separating any small liquid component from the solid wastes, thus enabling this liquid component to be collected and disposed of separately from the solid component. The closest prior art to the invention can be identified as the published European patent application EP 2 125 352 (Screw press for compacting solid waste) and the published U.S. Pat. No. 2,397,758 (Pulping machine). The former patent application discloses the use of a first horizontal waste feeding screw limited to a single cylindrical spiral or helix, of limited length, attached at one end to and projecting from support and rotation means, and the use of a screw press which can be located axially in the feed spiral or which can be positioned parallel to and outside the spiral in a separate housing, to receive the wastes which have been fed and initially pressed by the first spiral and to compact them, with the aid of calibrated constriction means which operate at the discharge opening of the press. Drainage means are provided at the base of the stator of the first feed spiral, where any liquid present in the waste tends to accumulate by gravity, for the collection and removal of this liquid. The latter of the aforementioned patents relates to a press having a stator body in the form of a truncated cone with a horizontal axis, in which there is an axially rotatable shaft to which are fixed the ends of a transport spiral which operates at a short distance from the inner longitudinally ribbed surface of the conical body, a plurality of curved blades, suitably offset from each other, being mounted on this shaft. The end of the stator of the device having the greater diameter has an opening in its upper part with a hopper for feeding the product to be pressed, while the lower part of the end of the stator of the device having the smaller diameter has a discharge opening closed by a hatch which can be opened manually. The lower part of the stator of the device is pierced and is surrounded externally by a chamber for collecting liquid which can be discharged by gravity. The product to be pressed is pushed from the wider to the narrower end of the device, by the action of the transport spiral, and is pressed by the force of this spiral, by the progressive decrease in pitch and by the progressive constriction of the cross section of the spiral and of the conical stator in which the spiral rotates, while the product is progressively shredded by the curved blades which have a progressive cutting action with a reduced force on the drive shaft of the device. The liquid produced by the pressing is collected in the drainage circuit lying below and the spent compacted material is discharged through the final discharge opening when it is cyclically opened.
The first of the aforesaid devices cannot be constructed with smaller overall dimensions, since the screw press is positioned horizontally, and therefore the material leaving the discharge opening has to be collected by means extending under and beyond this opening, thus unavoidably increasing the overall dimensions of the device in plan view. The second of the aforesaid devices has a simpler construction than the first, but is subject to the same problem as the first device and cannot provide the required degree of compaction. If this device were positioned with its axis vertical and with the discharge at the bottom, in order to occupy a smaller area in plan view, it would no longer be capable of separating the liquid component from the solid component of the pressed product.